A quantum theory of gravity is a holy grail for a certain breed of physicist because all physics except for gravity is well described by quantum laws 对于钻研某些研究的物理学家而言，量子重力论是最后的圣杯，因为除了重力之外，其它的物理都可以用量子定律来描述。
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Although the quantum laws are thought to be valid for objects of all sizes ? from elementary particles to the universe as a whole ? we do not usually see matter waves or any other quantum behavior in our everyday world 虽然量子定律应该适用于各种不同大小的物体（从基本粒子到整个宇宙） ，但在日常生活里，我们通常看不到物质波或是其他的量子现象。
